416 stainless steel pole pieces and slugs

[bajaman]

Hello folks
Does anybody know where i might obtain some 416 stainless pole screws and slugs by any chance ?
I can get 5000 of each from a manufacturer in China (15 cents each) but that is a lot more pieces than i need.
Has anybody actually tried using these in their pickups (excluding Gibson - lol) ?
Cheers
Steve

[Jason Rodgers]

The SD Dimebucker has stainless blades, but I don't know what grade of stainless. Is 416 a particular type that works well with magnets?

[salvarsan]

Find a local machine shop and ask for samples. Specify lightly chamfered tumbled slugs in a type 400 stainless alloy, type 430 if possible. They will tell you what is possible.

Since it is a very small job, pay them their minimum shop rate so they'll take you seriously.

[bajaman]

Thanks salvarsan, but here in New Zealand we are very limited with stainless choices - 304 and 316 are very easy to obtain but no supplier in NZ lists 416 grade, which is why i am trying China not local. 416 is quite commonly used in gun barrels apparently, but here in new Zealand nobody manufactures guns as far as I know. What appeals to me with 416 is the almost complete absence of nickel and of course the addition of at least 15% Chromium. i have found nickel plated pole screws to sound ice picky bright when compared to unplated 1018 or 1022 steels. 416 grade stainless has even less carbon than 1018 too, which is always a good thing with magnetic poles. incidentally 1215 bright steel is available locally and I have cut slugs with this material - it has got me closer to what I am looking for soundwise - maybe because it has very low carbon content - lower than 1018 steel at .09% ! I cannot seem to find anyone selling 1215 pole screws but i would sure be interested in trying them as well if they were to be made available.
I have some Seymour Duncan antiquities humbuckers - the pole screws and the slugs appear to be unplated and possibly stainless steel - they give the sound and dynamic reponse characteristics that I have been searching for, but I do not expect SD to tell me what they are - let alone sell them to me - lol.
I purchased a small quantity of Lindy Fralin pole screws from Angela instruments on Ebay - they are readily available in sets of six. They are the brightest and highest output nickel plated pole screw I have tried - and i have tried quite a few from Mojotone, Addiction FX, Crazy Parts etc. Unfortunately they do not sound anything like the SD antiquities pole screws. I have even tried the SD screws in a cheap Chinese humbucker and the improvement in tone and dynamic picking response was audible. Surely someone has had experience with 416 stainless steel that they are willing to share an opinion, before I commit to 5000 pieces from china. After all, i am only interested in building a dozen humbuckers not interested in going into full scale production at 65 years of age - lol.

[AletheianAlex]

I haven’t tried 416, but i HAVE messed with other grades of stainless lately. From my tests compared to 1xxx low-carbon, stainless gives you a slightly higher resonant freq and a higher Q on your peak because of the higher resistivity and slightly-lower permeability. I say try it, but do it on the cheap at first if you can before you go ordering thousands.

416 is a martensitic grade though, which has somewhat drastically-varying magnetic properties depending on hardness, etc. 430/430f/430fr/18-0/etc is a ferritic grade, and would be more predictable from one piece to another; it also has a relative permeability about twice what 416 has, and is closer to the typically-used 1xxx low carbon steel grades.

If you are looking for standard pole diameter to try out, stainless rod in 416 or 430 is pretty cheap, and you can find it online in .187” for slugs. Try some on your own before paying a machine shop, it cuts easy with a hacksaw (bit dulls the blades quickly because it seems to smear) or a dremel cutoff wheel and a file, especially if the rod stock comes annealed.

Also, if you want to do some REALLY cheap experimentation, 18-0 is basically the cutlery/flatware/hardware naming equivalent of 4xx-series ss (18 = chrome percentage and 0 = nickel), so if you go to a second hand shop with your magnet, you should be able to dig up enough to experiment with. The other cutlery ss grades are 18/10 and 18/8 which are closer to 3xx and not magnetic (unless they have been banged around a lot, then they are only SLIGHTLY magnetic), so it is easy to tell which you have in your hand. My first stainless experiments used blade poles made from butter knives and slugs made from a BBQ Kebab skewer before I gained enough confidence in the material to order full sheets.

I tend to use onlinemetals.com and Mcmaster-Carr when i can… not sure if they ship affordably to New Zealand, but I just took a peek and a foot of 416 ss starts at a little over a dollar at onlinemetals. Most stainless fillister screws seem to be 3xx 18/8, but I remember stumbling across some in 18/0 430, so they do exist if you are willing to fish for them online and make a few calls. If you just want to experiment, you could tap some threads into 1/8” rod and try that until you dig up the screws or have a shop make some. OR, you could check out jewelry supply. 430,18/0 stainless is sometimes used used for hypoallergenic jewelry (usually 3xx though, which won't work), so you might be able to dig up something the right diameter there.

Hope that is helpful.

[Jason Rodgers]

Also, if you want to do some REALLY cheap experimentation, 18-0 is basically the cutlery/flatware/hardware naming equivalent of 4xx-series ss (18 = chrome percentage and 0 = nickel), so if you go to a second hand shop with your magnet, you should be able to dig up enough to experiment with. The other cutlery ss grades are 18/10 and 18/8 which are closer to 3xx and not magnetic (unless they have been banged around a lot, then they are only SLIGHTLY magnetic), so it is easy to tell which you have in your hand. My first stainless experiments used blade poles made from butter knives and slugs made from a BBQ Kebab skewer before I gained enough confidence in the material to order full sheets.

I can very much appreciate your use of hacked up cutlery to experiment with metals!

Since I'm interested in trying out typical hardware store stainless screws, I'll ask the elementary question: what's the difference between putting a magnet on a 3xx "non-magnetic" stainless screw and a 4xx "magnetic" screw? Some basic reading on the interwebs tells me that a ferritic stainless steel will stay slightly magnetized after being exposed to a magnetic field, but an austenitic stainless steel will not. But will both of the them transfer or divert a magnetic field sufficiently for pickup pole purposes?

[bajaman]

I checked the knife drawer and i have some AISI420 knives - very similar chemical composition to AISI416, so may have to try hacking them up, but i bet it is really hard to cut with a hacksaw - lol.

[Richard]

Even 3xx stainless is hard to cut compared to 10xx. A knife blade will be much harder. I was just fooling around with a magnet in my kitchen, my utensils (18/0 I believe) show very little attraction to a magnet and don't seem to transfer magnetism (when holding to the magnet it doesn't want to stick to anything). My magnet didn't stick at all to my pans (18/8 I believe). Knives (high carbon stainless something similar to 4xx) stuck okay but didn't transfer magnetism well. This would seem to completely alter the parameters of of pickup. This was a couple of minutes of casual experimenting, nothing scientific.

[bajaman]

I may be able to get a small quantity of 420 in screws and slugs - just waiting for the quote from China. From what I can tell 420 has a small amount of nickel and slightly higher carbon content so may work - what do you guys think ?

[LtKojak]

I'd like to know WHY exactly are you so fixated with this particular alloy?

What exactly are trying to achieve?

Inquiring minds would like to know.

[bajaman]

Hello Pepe
I have tried most of the low carbon steels available from different suppliers - none of them come anywhere near the Seymour Duncan Antiquities Humbucker pole piece screws. the closest i have got is using 1215 unplated slugs and 1022 unplated screw poles.
I have noticed that the pole pieces in the SDAH pickups are NOT regular low carbon steel and they are unplated. They appear to be a grade of magnetic stainless steel as do the unplated slugs. This is why i am keen to hear if anyone else on this forum has tried 416, 420, or 430 stainless steel screws and slugs and what they found.
According to Alex "I haven’t tried 416, but i HAVE messed with other grades of stainless lately. From my tests compared to 1xxx low-carbon, stainless gives you a slightly higher resonant freq and a higher Q on your peak because of the higher resistivity and slightly-lower permeability. I say try it. " Salvarsan seems to give a nod toward 430 in his earlier post. Have you had any experience with SS alloys by any chance ? Cheers Steve.

[AletheianAlex]

Careful though, 420 steel is hardenable, so that would be darned near impossible to cut if it is heat treated to hold a knife edge. Same with 440 and 416. But 430 is not particularly hardenable.

Also, I don’t know if you guys have hobby shops down there with the little cellophane bags of metal shaped and sheets, but I have found that some of the stainless packages are annealed 430 ss. Also, places that so stainless countertops and backsplashes for kitchens usually carry 430 stainless as a cheaper alternative to 316L, and some of them do laser cutting. I don’t know if any do screws and rods though, but if anyone is looking for blade cores, that is another option.

I dug up some of the tests I did on mini-humbucker blade poles to give you a ballpark idea of what is going on. Again, no 416, just 430. I know you are talking about slugs and screws and not blades, but this is just what data I had on hand. Here is a graph of sweeps of an overwound mini-hum coil with different cores: low-carbon steel, 430 ss, m-19 transformer laminations, and grade 77 ferrite.



In my notes, I have 430ss resistivity listed as 0.000612 ohm-m, 1010 at 0.000143 ohm-m, and the initial relative permeability is pretty close between the two, so you end up with a similar resonant freq that just has a slightly higher peak. In the short lengths we use guitar pole material, the permeability as it effects inductance is dominated by geometry anyway. (The laminations and ferrite are just for reference, but they both have even higher resistivity and permeability, so the res peak is higher in amplitude and lower in freq.)

I wanted to post some gauss tests, but I am rearranging my shop and I can’t find my meter at the moment. I’ll post some results here when it turns up.

I know that does not give direct data on slugs and screws, but the effect should be similar, and if you find that it is a path you want to take, there are either shops that specialize in making custom screws, OR regular machine shops with screw machines. The few that I have looked into in the past have had custom orders starting at $500 for 1000 pc, but that was for standard materials and parts, so I am not sure about 5-40 fillister stainless humbucker screws... might be in the same ballpark or it might be considerably more. Maybe someone else on this forum would have a better lead on that for you.

[bajaman]

Thanks so much for your observations Alex - I have been playing around with transformer laminations and ferrites as well ;-)
Cheers
Steve

[Richard]

How audible are those differences? Would smaller polepieces have a similar effect as stainless? One thing that interests me is that I could alter the sound of commercially available pickups by swapping out the polepieces.

[LtKojak]

Hello Pepe
I have tried most of the low carbon steels available from different suppliers - none of them come anywhere near the Seymour Duncan Antiquities Humbucker pole piece screws. the closest i have got is using 1215 unplated slugs and 1022 unplated screw poles.
I have noticed that the pole pieces in the SDAH pickups are NOT regular low carbon steel and they are unplated. They appear to be a grade of magnetic stainless steel as do the unplated slugs. This is why i am keen to hear if anyone else on this forum has tried 416, 420, or 430 stainless steel screws and slugs and what they found.
According to Alex "I haven’t tried 416, but i HAVE messed with other grades of stainless lately. From my tests compared to 1xxx low-carbon, stainless gives you a slightly higher resonant freq and a higher Q on your peak because of the higher resistivity and slightly-lower permeability. I say try it. " Salvarsan seems to give a nod toward 430 in his earlier post. Have you had any experience with SS alloys by any chance ? Cheers Steve.

I'd use what's available and simply tweak the wind.

HTH,